Machine for crimping thermoplastic filament

ABSTRACT

The invention relates to a machine for crimping thermoplastic filament, in which the filament is conducted from a spool over a first thread guide through a thread-drawing device, through a second thread guide, through a heating oven, then through a false twister rotating about its axis, and finally over another threaddrawing device onto a spool.

I United States Patent 51 3,645,081

Salama Feb. 29, 1972 [54] MACHINE FOR CRIMPING 3,270,492 9/1966 Fitton et al ..57/34 HS THERMOPLASTIC FILAMENT 3,461,658 8/1969 Hampel ...57/l57 TS 3,474,612 10/1969 Jenkins et a1. ..57/34 HS [72] inventor: Risto Salama, Tapiola, Finland FOREIGN PATENTS OR APPLICATIONS [73] Assrgnee: Spinner Osakeyhtro, Helsinki, Finland 991,900 5/1965 Great Britain ..57/34 HS [22] Filed: Dec. 24, 1969 [2 App] No: 888,012 Primary ExaminerJohn Petrakes Attorney-Waters, Roditi, Schwartz & Nissen [30] Foreign Application Priority Data [57] ABSTRACT Oct. 31, I969 Finland "3135/69 The invention relates to a machine for crimping thermoplastic filament, in which the filament is conducted from a spool over [52] US. Cl. ..57l34 HS, 57/ 106 a first thread guide through a thread-drawing device, through [51 1 Int. ..D02g 1/02 a second thread guide, through a heating oven, then through a [58] Field of Search ..57/34 HS, 157 TS, 106 false twister rotating about its axis, and finally over another thread-drawing device onto a spool.

[56] References Cited 6 Claims, 3 Drawing Figures UNITED STATES PATENTS 3,166,881 1/1965 Servage.. ...,.,.57/ HS MACHINE FOR CRIMPING THERMOPLASTIC FILAMENT The invention is characterized in that the second thread guide which is placed between the first thread-drawing device and the heating oven consists of a roll journaled so as to be freely rotatable and which is caused to be rotated by the filament thread contacting it peripherally, and which includes on its peripheryguiding elements for guiding the thread along a tortuous path.

Finishing of thermoplastic filament, e.g., nylon filament into completed crimped threadready for use is carried out in that the filament is at first extruded. In extruded filament, the polymer chains are usually disoriented, in view of which the filament has generally little strength and the surfaceof the filament has a sticky and uneven fee]. In order to eliminate these drawbacks, the filament is stretched to 3-4 times its length, whereby the polymer chains are oriented. The strength of the filament thus increases and its surface becomes smooth and dense. The speed at which the stretched filament is drawn is usually approximately 700 meters per minute.

The stretched filament is then crimped, that is, it is given a false twist. In recent times crimping machines have been developed inwhich the speed of the filament approximates the above-mentioned drawing speed of the stretched filament. As a result, it has become possible to combine the stretching and crimping operations so as to be effected consecutively in one and the same machine.

The object of the present invention is to provide such a combined machine for crimping thermoplastic filament, in which the filament is conducted in operative sequence from a spool 'overa thread brake, through a thread-drawing device, thread guide, through a heating oven, a false twister rotating about its axis, and finally through another thread-drawing device onto a spool.

Heretofore, these types of machines have presented certain difficulties during operation, particularly when manufacturing filament or thread having a great number of false'twists per unit length of filament. It is noted that the twists move backward orupstream along the thread so that they already are produced at the first thread-drawing device. There, they tend to displace the thread, which makes one or several turns around thedevices drawing roll, in the axial direction of the drawing roll, so that the thread is caused to fall off the roll or to become tangled.

It has previously been suggested in order to eliminate this drawback, to conduct the thread, after passing through the first drawing device, through one or several stationary thread guides wherein the thread forms an angle, which prevents backward or upstream displacement of the twist. However, this angle causes increased tension on the thread, which may result in breakage of the thread.

The object of the present invention is to prevent the backward or upstream displacement of the twist extending as far back as the first drawing device without imparting any appreciable increase in the tensionon the thread. The invention is characterized in that the thread guide between the first thread-drawing device and the heating oven consists of a freely rotatablyjournaled roll to which the thread imparts rotation motion when it contacts this roll about its periphery, and on the periphery of which there are guiding elements for directing the thread into a predetermined tortuous path. This tortuous'path prevents the twists in the thread from being displaced farther backwards or upstream. The angles which are made in the thread by the roll do not increase the tension on the thread since the roll rotates in conjunction with the movement of the thread. The tension on the thread increases only in an amount commensurate with the bearing friction of the rapidly rotating roll. 1

The invention is now described in detail with reference to the accompanying drawing, wherein FIG. 1 schematically illustrates a machine according to the invention,

FIG. 2 shows the thread guide located between the first thread-drawing device and the heating oven, illustrated on a larger scale, and

FIG. 3 illustrates another embodiment of the invention shown in FIG. 2.

The unstretched extruded thermoplasticfilament 1 extends from the spool 2 and passes through the thread guides 3 and 4 toward the thread brake 5, which consists of two rolls pressing against each other. The brake rolls are not freely rotatable but have a fixed speed imparted thereto so that the speed of the thread passing through the nip between them is about 200 m./min.

Downstream of the thread brake 5 a thread-drawing device 6 is located, which consists of a freely rotatable roll 7 and a positively driven roll 8, around both of which the thread is looped several times. The device 6 may be, for example, of the type disclosed in the German Pat. No. 1,232,312. The device 6 draws the filament from the brake at aspeed of about 700 m./min, whereby the filament is stretched during movement between thethread brake 5 and the thread-drawing device 6 to about 3.5 times its original length.

The filament is then conducted further through a thread guide having the shape of a roll, which is described hereinbelow in detail. The thread is then passed through a thread guide 10, an oven 11, a thread guide 12 and a false twister 13 toward another thread-drawing device 14, which may be similar in design to the thread-drawing device 6. The devices 6 and 14 operate, at substantially identical speeds. Finally, the thread is wound onto a spool 16 with the assistance of a roll 15.

When the false twister 13 rotates at a high speed, false twists are formed in the filament l, at a rate forming a high number of false twists per unit length therefor. These false twists are displaced backwards or upstream along the thread so that they are already formed at the first thread-drawing device 6. Here, they displace thethread, which passes several times around the rolls 7 and 8, towards one or the other end of the rolls 7 and 8 depending on the direction of twist, tending to cause the thread to either fall off the rolls or to be tangled against the flanges at theends of the rolls. I

In order to prevent this occurrence, the machine according to the invention provides for a special thread guide having the shape of a rotatable r0119, one embodiment of which is shown in FIG. 2. The filament 1 contacts the periphery of the roll 9, in which a zigzagging groove 17 is formed for guidance of the filament, and which prevents the false twists on the thread from moving upstream. The thread causes the roll 9 to rotate this roll being supported on a shaft 18 to be easily rotatable. The angles in the zigzag groove 17 may have magnitudes of between and The shaft 18 of roll 9 further supports two arms 19 and 20, which have at their respective free ends thread guides 21 and 22, through which the thread 1 passes. The arms 19 and 20 are pivotable into desired angular positions with respect to each other and they may be maintained in this position, e.g., by means of friction. In this manner it is possible to adjust the length of the contact path between the filament l and the guiding groove 17, whereby the contact length is kept as small as possible.

The embodiment according to FIG. 3 differs from the foregoing only in the respect in that the guiding groove has been replaced with oblique guiding pins 23, which force the thread 1 to follow a zigzagging path.

It is obvious to anyone skilled in the art that different embodiments of the invention may fall within the scope of the claims presented herein.

I claim:

1. Improvement in a machine for crimping thermoplastic filament thread including .a spool having a supply of said thread; a first thread guide; a first thread-drawing device forwarding saidthread from said spool over said thread guide; a second thread guide; a heating oven; a false twister; and a second thread-drawing device, said second thread-drawing A device being adapted to draw said thread from said first thread guide being positioned between said first thread-drawing device and said oven, said last-mentioned guide including a freely rotatable roll adapted to be rotated in response to said thread contacting the periphery thereof, and guide means on the peripheral surface of said roll for guiding the thread along a tortuous path.

2. Machine as claimed in claim 1, wherein said guide means on the peripheral surface of said roll comprises an essentially zigzag-shaped guide groove.

3. Machine as claimed in claim 1, wherein said guide means on the peripheral surface of said roll comprise a plurality of oblique guide pins adapted to impart a zigzag-shaped path to the motion of said thread.

4. Machine as claimed in claim 1, wherein said zigzagshaped path forms apex angles of magnitudes in the range of to 5. Machine as claimed in claim I, wherein said guide means include adjustable means for conveying said thread onto and from said roll peripheral surface at variable lengths of contact between the thread and the roll surface.

6. Machine as claimed in claim 5, said adjustable means including arms supported on said roll and extending therefrom, thread guides positioned on the free ends of said arms, said arms being pivotable into variable angular thread-guiding positions relative to each other. 

1. Improvement in a machine for crimping thermoplastic filament thread including a spool having a supply of said thread; a first thread guide; a first thread-drawing device forwarding said thread from said spool over said thread guide; a second thread guide; a heating oven; a false twister; and a second threaddrawing device, said second thread-drawing device being adapted to draw said thread from said first thread-drawing device so as to conduct said thread sequentially over said second thread guide, through said oven and said false twister, the improvement comprising said second thread guide being positioned between said first thread-drawing device and said oven, said last-mentioned guide including a freely rotatable roll adapted to be rotated in response to said thread contacting the periphery thereof, and guide means on the peripheral surface of said roll for guiding the thread along a tortuous path.
 2. Machine as claimed in claim 1, wherein said guide means on the peripheral surface of said roll comprises an essentially zigzag-shaped guide groove.
 3. Machine as claimed in claim 1, wherein said guide means on the peripheral surface of said roll comprise a plurality of oblique guide pins adapted to impart a zigzag-shaped path to the motion of said thread.
 4. Machine as claimed in claim 1, wherein said zigzag-shaped path forms apex angles of magnitudes in the range of 90* to 160* .
 5. Machine as claimed in claim 1, wherein said guide means include adjustable means for conveying said thread onto and from said roll peripheral surface at variable lengths of contact between the thread and the roll surface.
 6. Machine as claimed in claim 5, said adjustable means including arms supported on said roll and extending therefrom, thread guides positioned on the free ends of said arms, said arms being pivotable into variable angular thread-guiding positions relative to each other. 